Electronic device manufacturers strive to produce a rich interface for users. Conventional devices use visual and auditory cues to provide feedback to a user. In some interface devices, kinesthetic feedback (such as active and resistive force feedback) and/or tactile feedback (such as vibration, texture, and heat) is also provided to the user, more generally known collectively as “haptic feedback” or “haptic effects”. Haptic feedback can provide cues that enhance and simplify the user interface. Specifically, vibration effects, or vibrotactile haptic effects, may be useful in providing cues to users of electronic devices to alert the user to specific events, or provide realistic feedback to create greater sensory immersion within a simulated or virtual environment.
Haptic feedback has also been increasingly incorporated in portable electronic devices, such as cellular telephones, personal digital assistants (“PDA”s), portable gaming devices, and a variety of other handheld devices. For example, some portable gaming applications are capable of vibrating in a manner similar to control devices (e.g., joysticks, etc.) used with larger-scale gaming systems that are configured to provide haptic feedback. Additionally, devices such as cellular telephones and PDAs are capable of providing various alerts to users by way of vibrations. For example, a cellular telephone can alert a user to an incoming telephone call by vibrating. Similarly, a PDA can alert a user to a scheduled calendar item or provide a user with a reminder for a “to do” list item or calendar appointment.
For some applications, there is a need for a handheld device to include directional feedback, where the handheld device can indicate a direction (e.g., left, right, etc.) to the user. One known method for creating directional feedback is to place an actuator on the far right of the handheld device and the other on the far left, both grounded to the housing of the handheld device. However, because most handheld devices have a generally rigid housing, it is difficult to tell which actuator is actually moving the device, and it is difficult for a user to determine which actuator in the device is creating the vibration.
Based on the foregoing, there is a need for an improved directional haptic system and method for generating haptic effects for a touchscreen.